The invention relates generally to apparatus for detecting leaks of flammable fluids in pressure pipe lines, and more particularly to a self-energized, low voltage leak detector for use in service stations having a pressure pipe line for the intermitent-pressure flow delivery of gasoline from a storage tank.
In the closest prior art, Reynolds, U.S. Pat. No. 3,935,527 teaches a leak detector similar to the invention except that a timing circuit is energized from a local electrical power source by the cut-off pressure in a pressure pipe line. Cut-off pressures are variable between pressure pipe lines to provide a variable range of pressures for relating to the invariable time period of a timing circuit, and produces variable rates of leakage that may not be true.
In the invention, the predetermined pressure range is invariable as well as the predetermined time period, and when related produce true gasoline leakage rates for any pressure pipe line. Also the use of an included battery rather than a local electrical power supply to the pressure pipe line for energizing the leak detector ensures that energizing power supply will be unvaried by any overload of a local power supply.